make your task bar disappear XD
Get a program called Desktops it lets you have multiple desktops so you can switch to a totally new desktop with a new taskbar etc.
make your task bar disappear XD
Fear the old blood.
What's wrong with having your brother watching you play Katawa Shoujo?
Hell, invite the whole family over for a session of Yume Miru Kusuri!
But seriously. If you live in one of "Those" families, get yourself a cheap laptop, a pair of headphones and lock yourself in your chamber.
But more information on what you're trying to hide and for what reason could help..
Yes the Power Button.
You could tell him to fuck off?
Google search Double Desktop 2.0. I've been using for quite some time, and it works quite well.